Inherent characteristics of ultra-photosensitive Al/Cu–CeO2/p-Si metal oxide semiconductor diodes

Abstract

An ultrahigh photosensitive diode was developed using a Cu-doped CeO₂ thin film through spray pyrolysis processing, which has made a unique contribution in the field of optoelectronic device fabrication process. Phase identification revealed a good arrangement of atoms in the as-prepared nanostructured thin films via structural analysis. The formation of wire-shaped nanorods was confirmed. Elemental distribution and their valence states were systematically monitored using X-ray photoelectron spectroscopy analysis, where the presence of Ce³⁺ was evidenced. Good mechanical properties were obtained owing to the Cu-doping in the cerium host matrix, which was investigated by nano-indentation. Bandgap energy fluctuation was the root cause for electrical conductivity. The present work revealed a decrease in the band gap energy upon Cu-doping alters the electrical conductivity. An as-fabricated photodiode demonstrated superior detectability upon Cu-doping. In the depletion region, on account of a high surface-to-volume ratio, the generation of electron–hole pairs increased along with photoresponsivity with increases in the quantum efficiency and current gain.